Control knob with multiple degrees of freedom and force feedback

ABSTRACT

The present invention provides a control knob on a device that allows a user to control functions of the device. In one embodiment, the knob is rotatable in a rotary degree of freedom and moveable in at least one transverse direction approximately perpendicular to the axis. An actuator is coupled to the knob to output a force in the rotary degree of freedom about the axis, thus providing force feedback. In a different embodiment, the knob is provided with force feedback in a rotary degree of freedom about an axis and is also moveable in a linear degree of freedom approximately parallel to the axis, allowing the knob to be pushed and/or pulled by the user. The device controlled by the knob can be a variety of types of devices, such as an audio device, video device, etc. The device can also include a display providing an image updated in response to manipulation of the knob. Detent forces can be provided for the knob by overlapping and adjusting ranges of closely-spaced detents in the rotary degree of freedom of the knob.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and is a continuation of U.S.application Ser. No. 09/680,408, filed Oct. 2, 2000, now U.S. Pat. No.6,686,911, which is a continuation of U.S. application Ser. No.09/179,382, filed on Oct. 26, 1998, now U.S. Pat. No. 6,154,201, whichis a continuation-in-part of U.S. application Ser. No. 09/049,155, filedMar. 26, 1998, now U.S. Pat. No. 6,128,006, and U.S. application Ser.No. 09/087,022, filed May 29, 1998, now U.S. Pat. No. 6,061,004, whichis a divisional of U.S. application Ser. No. 08/756,745, now U.S. Pat.No. 5,825,308, filed Nov. 26, 1996, each of which is assigned to theassignee of the present application, and each of which is incorporatedin its entirety herein by reference.

BACKGROUND OF THE INVENTION

This invention relates generally to knob control devices, and moreparticularly to control knob devices including force feedback andadditional input functionality.

Control knobs are used for a variety of different functions on manydifferent types of devices. Often, rotary control knobs offer a degreeof control to a user that is not matched in other forms of controldevices, such as button or switch controls. For example, many usersprefer to use a rotating control knob to adjust the volume of audiooutput from a stereo or other sound output device, since the knob allowsboth fine and coarse adjustment of volume with relative ease, especiallycompared to button controls. Both rotary and linear (slider) knobs areused on a variety of other types of devices, such as kitchen and otherhome appliances, video editing/playback devices, remote controls,televisions, etc.

Some control knobs have been provided with “force feedback.” Forcefeedback devices can provide physical sensations to the usermanipulating the knob. Typically, a motor is coupled to the knob and isconnected to a controller such as a microprocessor. The microprocessorreceives sensor signals from the knob and sends appropriate forcefeedback control signals to the motor so that the motor provides forceson the knob. In this manner, a variety of programmable feel sensationscan be output on the knob, such as detents, spring forces, or the like.

One problem occurring in control knobs of the prior art is that theknobs are limited to basic rotary motion. This limits the controloptions of the user to a simple, one-degree-of-freedom device that doesnot allow a variety of selection options. In additions if force feedbackis provided on the knob, the limited control functionality of the knoblimits the user from fully taking advantage of the force feedback toprovide more control over desired functions.

SUMMARY OF THE INVENTION

The present invention provides a knob control interface that allows auser to control functions of a device in a variety of ways. Embodimentsof the knob controller include additional degrees of freedom for theknob and force feedback applied to the knob.

More particularly, in one embodiment a knob controller device of thepresent invention includes a knob coupled to a grounded surface. Theknob is rotatable in a rotary degree of freedom about an axis extendingthrough the knob, and the knob also moveable in a transverse directionapproximately perpendicular to the axis. A rotational sensor detects aposition of the knob in the rotary degree of freedom, and a transversesensor detects a position of the knob in the transverse direction. Anactuator is coupled to the knob to output a force in the rotary degreeof freedom about the axis, thus providing force feedback. In a preferredembodiment, the knob is moveable in multiple transverse directions. Forexample, the transverse sensor includes a switch that detects when theknob is moved in a transverse direction; the switch can be a hat switchhalving multiple individual switches, for example. In one embodiment,the knob is moveable in four transverse directions spaced approximatelyorthogonal to each other.

Furthermore, a local microprocessor can be included to control the forcefeedback on the knob. The microprocessor receives sensor signals fromthe rotary and transverse sensors and controls a function of a device inresponse to the sensor signals. The device can be any of a variety ofelectrical or electronic types of devices. The device can also include adisplay, wherein an image on said display is changed in response tomanipulation of the knob in the transverse direction. A method of thepresent invention for controlling functions of a device from inputprovided by a knob similarly uses sensor signals from a rotary sensorand a transverse sensor to control at least one function of a device,such as adjusting a frequency of a radio tuner or updating a displayedimage based on at least one of the sensor signals.

In another aspect of the present invention, a knob is coupled to agrounded surface, where the knob is rotatable in a rotary degree offreedom about an axis extending through the knob. The knob is alsomoveable in a linear degree of freedom approximately parallel to theaxis. A rotational sensor and a linear sensor detect positions of theknob in the respective degrees of freedom. An actuator is also coupledto the knob and operative to output a force in the rotary degree offreedom about the axis, thereby providing force feedback to the knob.The linear degree of freedom of the knob allows it to be pushed and/orpulled by the user, where the push or pull motion is detected by thelinear sensor. A spring member is preferably included for biasing theknob to a center position in the linear degree of freedom. The linearsensor can, for example, include a grounded switch that is contacted bya pusher member coupled to the knob when the knob is moved in the lineardegree of freedom. Alternatively, the linear sensor can detect aposition of the knob within a detectable continuous range of motion ofthe knob. The transverse degree of freedom of the previous embodiment ofthe knob can also be included. A microprocessor preferably receives thesensor signals and controls a function of a device in response to thesensor signals, and also sends force feedback signals to the actuator tocontrol forces output by the actuator.

In a different aspect of the present invention, a method for providingdetent forces for a force feedback control includes outputting a firstforce by an actuator on a user manipulatable object, such as a rotaryknob, for a first detent when the user object is moved within a range ofthe first detent. The first force assists movement of the user objecttoward an origin position of the first detent and resists movement awayfrom the origin position. A second force for a second detent is alsooutput on the user object when the user object is moved within a rangeof the second detent, similar to the first force. A portion of the rangeof the first detent overlaps a portion of the range of the seconddetent. The overlapped portions of the ranges preferably modifies thesecond force such that a force at the beginning point of the seconddetent range has less magnitude than a force at an endpoint of thesecond detent range. Preferably, the first force and second force eachhave a magnitude that increases the further that the user object ispositioned from that detent's origin. Preferably, the direction of theknob changes the range endpoint magnitudes Such that if the knob ismoved in the opposite direction, the first-encountered point of thefirst detent range has a lesser magnitude than the last-encounteredpoint.

In another aspect of the present invention, a method for providingdetent forces for a force feedback control includes defining a periodicwave and using at least a portion of the periodic wave to define adetent force curve. The detent force curve defines a force to be outputon a user manipulatable object, such as a rotary knob, based on aposition of the user manipulatable object in a degree of freedom. Thedetent force curve is then used to command the force on the usermanipulatable object as output by an actuator. The type, period andmagnitude can be specified for the periodic wave. The detent force curvecan be defined by specifying a portion of said periodic wave to be thewidth of the detent force curve, specifying a phase and an offset to beapplied to said periodic wave to define the detent force curve, and/orspecifying an increment distance between successive detents.

The apparatus and method of the present invention provide an controlknob for a device that includes greater control functionality for theuser. The lineal and transverse degrees of freedom of the knob allow theuser to select functions, settings, modes, or options with much greatercase and without having to take his or her hand off the knob. Forcefeedback may also be added to the knob to provide the user with greatercontrol and to inform the user of options and selections through thesense of touch. Force feedback detent implementations of the presentinvention provide overlapping detent ranges to allow more accuratecontrol of a knob by a user within closely-spaced detents, and anefficient, convenient method for defining detents from periodic waves.

These and other advantages of the present invention will become apparentto those skilled in the art upon a reading of the followingspecification of the invention and a study of the several figures of thedrawing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one embodiment of a device including acontrol knob of the present invention;

FIG. 2 is a diagrammatic view of a display allowing the user to use theknob of the present invention to select features of the device;

FIG. 3 a is a perspective view of one embodiment of the mechanism forimplementing the control knob of the present invention;

FIG. 3 b is a side elevational view of the embodiment of FIG. 3 a;

FIG. 4 a is a perspective view of a second embodiment of the mechanismfor implementing the control knob of the present invention;

FIG. 4 b is a top plan view of a unitary plate used in the embodiment ofFIG. 4 a;

FIG. 4 c is a side elevational view of the embodiment of FIG. 4 a;

FIG. 5 is a perspective view of a linear slider control of the presentinvention;

FIGS. 6 a–6 d illustrate nonoverlapping, overlapping, and hysteresisfeatures of force detent profiles;

FIGS. 7 a–7 e are graphs illustrating the creation of detent forceprofiles from periodic waves according to the present invention; and

FIG. 8 is a block diagram of a control system for the control knob ofthe present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 is a perspective view of an example of a control panel 12 for adevice 10 including a control knob of the present invention. In thedescribed embodiment, device 10 is an audio device that controls theoutput of sound, such as music or speech, from speakers that areconnected to the device 10. For example, a common embodiment of device10 is a stereo system that includes the ability to play sound from oneor more media or signals, such as cassette tapes, digital audiotransmission (DAT) tapes, compact discs (CD's) or other optical discs,or radio signals transmitted through the air from a broadcastingstation.

The device 10 can also include additional or other functionality notrelated to audio control and output. For example, many vehicles includeelectronic systems to control the temperature in the vehicle cabin (airconditioning, heat, etc.), as well as systems to provide information onthe current operating characteristics of the vehicle, such as currentspeed, engine temperature, fuel or other fluid levels, whether windowsof the vehicle are open, etc. Other systems may include a navigationsystem that displays a map and the current location of the vehicle withrespect to the map, a cellular telephone or other portable telephonecontrol system, and a security/alarm system. Device 10 can include theability to display information from and/or influence such other systemsin a vehicle or other environment, such as a house, office, etc.

Alternatively, device 10 can be a variety of other electronic orcomputer devices. For example, device 10 can be a home appliance such asa television set, a microwave oven or other kitchen appliances, a washeror dryer, a home stereo component or system, a home computer, a set topbox for a television, a video game console, a remote control for anydevice, a controller or interface device for a personal computer orconsole games, a home automation system (to control such devices aslights, garage doors, locks, appliances, etc.), a telephone,photocopier, control device for remotely-controlled devices such asmodel vehicles, toys, a video or Film editing or playback system, etc.Device 10 can be physically coupled to the control panel 12, or thepanel 12 can be physically remote from the device 10 and communicatewith the device using signals transferred through wires, cables,wireless transmitter/receiver, etc.

Device 10 preferably includes a front panel 12, a display 14, severalcontrol buttons 16, and one or more control knobs 18 of the presentinvention. Front panel 12 can be mounted, for example, on the interiorof a vehicle, such as on or below the dashboard, or in some otherconvenient area. Alternatively, the front panel 12 can be the surface ofthe external housing of the device 10 itself, such as a stereo unit. Thedevice 10 may include several functions, such as playing an audio track,adjusting volume, tone, or balance of an audio output, displaying allimage (icons, a map, etc.), or adjusting the temperature or fan speed ina vehicle, which can be changed or set by the user manipulating thecontrols of the device 10 on front panel 12.

Display 14 is provided to show information to the user regarding thecontrolled device or system and/or other systems connected to the device10. For example, options 20 can be displayed to indicate which functionof the device 10 is currently selected. Such options can include“radio,” “tape,” “CD,”, or power, as shown. Other information, such asthe current radio frequency 22 selected for a radio tuner, can also bedisplayed. Furthermore, any information related to additionalfunctionality of the device 10 can also be displayed. For example,information 24 can be provided to allow the user to select one or morefunctions not related to the audio operation of the device 10. In someembodiments, a map or similar graphical display can be shown on display14 of all device 10 to allow the user to navigate. Some examples offunctions displayed by a display 14 are shown with respect to FIG. 2,below. In other embodiments, display 14 can be a separate monitordisplaying a graphical user interface or other graphical environment ascontrolled by a host computer. Display 14 can be any suitable displaydevice, such as an LED display, LCD display, gas plasma display, CRT, orother device. In some embodiments, display 14 can include atouch-sensitive surface to allow a user to touch displayed imagesdirectly on the display 14 to select those images and an associatedsetting or function.

Control buttons 16 are often provided on device 10 to allow the user toselect different functions or settings of the device. For example, on anaudio device, buttons 16 can include radio station preset buttons,rewind/fast forward tape functions, power, speaker loudness, etc.Virtually any function of the device can be assigned to buttons 16. Thebuttons 16 may also be used in conjunction with the control knobs 18, asdescribed below.

Control knobs 18 are provided to allow the user a different type ofcontrol of functions and settings of device 1I than the buttons 16allow. Knobs 18, in the described embodiment, are approximatelycylindrical objects engageable by the user. The knobs 18 canalternatively be implemented as a variety of different objects,including conical shapes, spherical shapes, dials, cubical shapes, rods,etc., and may have a variety of different textures on theircircumferential surfaces, including bumps, lines, or other gripe, oreven projections or members extending from the circumferential surface.In addition, any of variety of differently-sized knobs can be provided;for example, if high-magnitude forces are output, a larger-diametercylindrical knob is often easier for a user to interface with device 10.In the described embodiment, each knob 18 rotates in a single rotarydegree of freedom about an axis extending out of the knob, such as axisA. The user preferably grips or contacts the circumferential surface 26of the knob 18 and rotates it a desired amount. Force feedback can beprovided in this rotary degree of freedom in some embodiments, asdescribed in greater detail with reference to FIGS. 3 a and 3 b.

Furthermore, the control knobs 18 of the present invention allowadditional control functionality for the user. The knobs 18 arepreferably able to be moved by the user in one or more directionsapproximately perpendicular to the axis A of rotation, e.g. parallel tothe surface of the front panel 12 as shown in FIG. 1 (“transversemotion” or “transverse direction”). This transverse motion is indicatedby arrows 28. For example, the knob 18 can be moved in the fourorthogonal directions shown, or may be moveable in less or moredirections in other embodiments, e.g. only two of the directions shown,or in eight directions spaced at 45 degree intervals about axis A. Inone embodiment, each transverse direction of the knob is spring loadedsuch that, after being moved in a direction 28 and once the userreleases or stops exerting sufficient force on the knob, the knob willmove back to its centered rest position. In other embodiments, the knobcan be provided without such a spring bias so that the knob 18 stays inany position to which it is moved until the user actively moves it to anew position.

This transverse motion of knob 18 can allow the user to selectadditional settings or functions of the device 10. In some embodiments,the additional control options provided by knob 18 allow the number ofbuttons 16 and other controls to be reduced, since the functionsnormally assigned to these buttons can be assigned to the knob 18. Forexample, the user can move a cursor 30 or other visual indicator ondisplay 14 (e.g. pointer, selection box, arrow, or highlighting ofselected text/image) to a desired selection on the display. Thus, thecursor 30 can be moved from the “radio” selection shown to the “tape”selection by moving the knob 28 in the down direction as shown inFIG. 1. Or, the cursor 30 can be moved to the “CD” selection by movingthe knob 28 in the direction to the right. If knob 18 is provided withdiagonal directions (e.g. at 45 degree intervals), the user can move thecursor 30 from the “radio” selection directly to the “off” selection.The user can similarly move cursor 30 or a different indicator to theother information settings 24, to the frequency display 22, or to anyother displayed option, setting, or area/region on the display 14.

Besides such a cursor positioning mode, the transverse motion of knob 28can also directly control values or magnitudes of settings. For example,the left motion of knob 18 can decrease the radio station frequencyvalue 22, where the value can (decrease at a predetermined rate if theuser continually holds the knob 18 in the left direction. The rightmotion of the knob 18 can similarly increase the frequency value 22. Inanother example, once one of the information settings 24 is selected, asub menu can be displayed and the directions 28 of knob 18 can adjustair temperature, a timer, a cursor on a displayed map, etc.

Different modes can also be implemented; for example, the default modeallows the user to control cursor 30 using the directions 28 of theknob. Once the cursor is located at a desired setting, such as thefrequency value 22, the user can switch the mode to allow the directions28 to control the setting itself, such as adjusting the value 22. Toswitch modes, any suitable control can be used. For example, the usercan push a button, such as button 29, to toggle a mode. Alternatively,the user can push or pull the knob 18 to select the mode; thisfunctionality of the present invention is described below. Or, some orall of the directions 28 can be used to select modes; for example, thedown direction might switch to “volume” mode to allow the user to rotatethe knob to adjust volume; the up direction can switch to “adjust radiofrequency” mode, and the left direction can switch to “balance” mode(for adjusting the speaker stereo balance for audio output with rotationof knob 18).

In addition, the control knobs 18 are preferably able to be pushedand/or pulled in a degree of freedom along axis A (or approximatelyparallel to axis A). This provides the user with additional ways toselect functions or settings without having to remove his or her gripFrom the knob. For example, in one preferred embodiment, the user canmove cursor 30 or other indicator on the display 14 using the directions28 of the knob 18; when the cursor has been moved to a desired settingor area on the display, the user can push the knob 18 to select thedesired setting, much like a mouse button selects all icon in agraphical user interface of a computer. Or, the push or pull functioncan be useful to control the modes discussed above, since the user cansimply push the knob and rotate or move the knob while it is in thepushed mode, then release or move back the knob to select the othermode. The modes discussed above can also be toggled by pushing orpulling the knob 18. The push and/or pull functionality of the knob 18can be provided with a spring return bias, so that the knob returns toits rest position after the use releases the knob. Alternatively, theknob can be implemented to remain at a pushed or pulled position untilthe user actively moves the knob to a new position.

A slider control 32 of the present invention may also be included indevice 10. Slider control 32 includes a slider knob 34 which is graspedby the user and moved in a linear direction as shown by arrow 36. In thepresent invention, slider control 32 preferably includes force feedbackfunctionality. Thus, as the user moves the knob 34, force sensationssuch as a spring force, a damping force, jolts, detents, textures, orother forces can be output and felt by the user. Furthermore, the sliderknob 34 can include a button 38 which can be pressed by the usersimilarly to the push knob embodiment discussed above with reference toknob 18. Alternatively, the knob 34 can be pushed and/or pulledsimilarly to the knob 18 as described above. Slider control 32 cancontrol any of the various functions, settings, or options of the device10. For example, the motion left or right of knob 34 can control theradio frequency 22, where force detents are output for each stationand/or each preset station previously programmed by the user. Or, thecursor 30 can be moved using the slider knob 34, such that when thecursor reaches a desired setting or selection, the user can push button38 or push on the knob 34 to select that setting. Other functions suchas volume, balance, tone, map functions, temperature functions, or modeselection can also be controlled by the slider control 32. Slidercontrol is described in greater detail with respect to FIG. 5.

FIG. 2 is an example showing images which can be displayed on display 14to assist the user in selecting options with knobs 18 and/or slidercontrol 32. Display 14 can present icons as shown, in this example forthe control of audio output signals from device 10. Icon 46 is selectedto control the volume of the audio output using knob 18, where thecircular pointer 42 can be moved in accordance with the knob 18. Icon 47is used to control the frequency of the radio tuner (the currentselected frequency can be displayed as well), and the icons 48, 49, and51 are used to control the balance, treble, and bass of the audio,respectively. For example, the indicator 44 can be moved left or rightdepending on the current setting. Cursor 45 is used to select one of theicons to allow the control of the functions associated with the selectedicon. Cursor 45 indicates which of the icons in display 14 are currentlyselected. The icon can be moved from each icon to the next by rotatingthe knob 18. Alternatively, the transverse motion of the knob can movethe cursor 45. A function of the device designed by the selected iconcan be selected by pushing the knob 18 in the linear direction. Thecursor can be a square or other-shaped box, or the currently-selectedicon can be highlighted to indicate the cursor's location.

It should be noted that each of the icons can preferably be set to aposition control mode or to a rate control mode as desired by the user.For example, the user may select position control for volume 46 and ratecontrol for the functions of icons 47, 48, 49, and 51, or any othercombination. In position control mode, force detents are preferablyoutput to indicate particular settings or how far the knob 18 has beenrotated. In rite control mode, detents can also be output. For example,the user maintains the knob 18 at a rotary position away from the centerposition in opposition to a spring return force, and a detent force(e.g., jolt) is output to indicate how much a particular value has beenchanged. For example, a jolt can be output for each 10 MHz of frequencythat is increased, or for each particular amount of treble or bass thathas been adjusted.

Other icons can be displayed in other embodiments. For example, an forvent location can be selected using cursor 45 to determine which ventsin the car provide air flow, where a top vent, a bottom vent, or bothtop and bottom vents can be selected. A fan speed icon can be selectedto choose a fan speed setting for the air flow from the vents in thecar. In a preferred force feedback implementation, once the fan speedicon has been selected by pushing in the knob 18, the user may rotatethe knob 18 to select the fan rotation speed in a position control mode.A small vibration can be output on the knob 18 in the rotary degree offreedom, where the frequency (or magnitude) of the vibration forcescorrelate with the magnitude of fan rotation speed, i.e., a high fanspeed provides a fast vibration. Furthermore, detents are preferablyoutput superimposed on the vibration forces so that the user can feelthe fan settings at the detents. This allows the user to select fanspeed based purely on tactile feel, so that the driver need not look atthe display 14. A temperature icon can be selected to adjust thetemperature in the car. The temperature can preferably be adjusted byrotating knob 18, where force detents indicate each temperature setting.Icons for moving mechanical components, such as seats or mirrors, can beprovided, where a rate control force mode is used to control theposition of the components.

FIG. 3 a is a perspective view and FIG. 3 b is a side elevational viewof one implementation of control knob 18 of the present invention. Inthis implementation, knob 18 includes the ability to move transverselyin four directions, and the knob 18 can also be pushed for additionalselection ability.

Knob 18 is rigidly coupled to a rotatable shaft 50 which extends throughthe grounded front panel 12 (shown in dashed lines). Shaft 50 extendsthrough a four-way switch 52 which detects the transverse motion of theknob 18 in directions 28. The knob 18 is biased toward the centered restposition within switch 52 by a spring member 64, described in greaterdetail below. When the shaft 50 is moved in any of the providedtransverse directions, a corresponding micro switch (not shown) includedon the interior sidewall of the four-way switch 52 is closed, thuscausing a signal to be output on leads 54. Thus, switch 52 preferablyincludes individual micro switches, one for each provided transversedirection (four individual switches in the described embodiment). Asuitable switch for use as switch 52 is a “hat switch” which is commonlyprovided for analog joystick controllers for personal computers andallows 4 or 8 directions to a moveable member. For example, joystick hatswitches manufactured by such companies as CH Products, Inc. or Logitechcan be used. In other embodiments, two-way, eight-way, or other types ofswitches can be used, depending on how many directions are desired.

A pusher member 56 is rigidly coupled to shaft 50 next to the switch 52.Since the switch 52 includes an aperture through which the shaft 50extends, the knob 18, shift 50 and pusher member 56 are operative tomove as a unit along axis A with respect to the front panel (ground) andthe switch 52. A switch 58 (see FIG. 3 b) is coupled to a groundedmember 60 and is provided in the path of the pusher member 56. Thus,when the knob 18 is pushed by the user, the shaft 50 and the pushermember 56 are moved along axis A in a direction indicated by arrow 62(see FIG. 3 b). This causes pusher member 56 to engage the button 64 ofthe switch 58, causing the button 64 to be pushed inward and close (oropen) the switch. The pushing motion of the knob 18 is thus sensed.

In other embodiments, a sensor can be provided to sense a range ofpositions of the knob 18 or a continuous motion of the knob 18 linearlyalong axis A. For example, a Hall effect switch can be provided onpusher member 56 which measures the position of the pusher member 56relative to a grounded magnet on member 60 (or the Hall effect switchcan be placed on the member 60 and the magnet can be placed on themember 56). Or, an optical sensor (such as a photodiode) or other typeof sensor can detect the position of the member 56 and/or knob 18. Insuch an embodiment, the position of the knob along axis A canproportionately control a function or setting of the device 10. Forexample, such movement can control the volume of audio output of thedevice, motion of a cursor across a display, or the brightness of lightsinside a vehicle.

A pull switch can be implemented similarly to the push switch shown inFIGS. 3 a and 3 b. For example, a switch similar to switch 58 can begrounded and provided on the opposite side of pushed member 56 so thatwhen knob 18 is pulled in a direction opposited to direction 62, abutton on this switch is engaged by the pusher member to detect thepulled motion. The pull motion of knob 18 can also be sensed in acontinuous range similar to the push embodiments described above. Insome embodiments, both push and pull motions of the knob 18 may beprovided and sensed.

A spring member 64 is rigidly coupled to the pushing member 56 at oneend and is rigidly coupled to a rotatable end member 66 at its otherend. Spring member 64 is compressed when the knob 18 and pusher member56 are moved in the direction of arrow 62. Spring member 64 thusprovides a spring force that biases the knob 18 in the directionopposite to direction 62. If the knob 18 is not forced in direction 62,the spring bias moves the knob 18 opposite to direction 62 until theknob reaches its rest position. In those embodiments including a pullmotion of the knob 18 in the direction opposite to direction 62, aspring member can be included on the opposite side of pusher member 56to spring member 64, to bias the knob 18 in direction 62 after the userhas pulled the knob. In yet other embodiments, no spring member 64 isprovided, and the knob 18 remains at any pushed or pulled position untilactively moved to a new position by the user.

Spring member 64 also provides the transverse motion of knob 18 in thedirections 28. The flexure of the spring element allows the knob to movein transverse degrees of freedom, while still being relativelytorsionally stiff to allow forces to be transmitted effectively from anactuator to the knob 18 about axis A. In other embodiments, other typesof couplings can be provided to allow a pivot or translational motion inthe directions 28. For example, flexible disc servo couplings orone-piece flexible shaft disc couplings can be provided; such couplingsare available from Renbrandt, Inc. of Boston, Mass. and Helical ProductsCompany, Inc. of Santa Maria, Calif. In other embodiments, bent spaceframes provided in a square-plate coupling or a rectangular coupling canbe used. Furthermore, a different alternate flexible coupling embodimentis described in greater detail with respect to FIGS. 4 a–4 c.

End member 66 is coupled to a rotatable shaft 68 of an actuator 70. Thehousing 72 of actuator 70 is rigidly coupled to grounded member 74, andthe shaft 68 rotates with respect to the housing 72 and the member 74.Actuator 72 can be controlled to output force on rotating shaft 68 aboutaxis A, thus driving the shaft and all components rigidly coupled to theshaft about axis A. The shaft 68 thus rotates end member 66, springmember 64, pusher member 56, shaft 50, and knob 18. The output force onknob 18 is felt by the user as force feedback. Actuator 70 can be any ofa variety of different types of actuators, including a DC motor, voicecoil, pneumatic or hydraulic actuator, magnetic particle brake, etc. Asensor 76 has a shaft rigidly coupled to the rotating shaft 68 of theactuator 70 and thus detects the rotation of the shaft 68 and the knob18 about axis A. Sensor 76 is preferably a digital optical encoder butcan alternatively be a different type of sensor, such as an analogpotentiometer, a photodiode sensor, a Hall effect sensor, etc.

The force feedback output on knob 18 can include a variety of differentforce sensations. The force feedback can be integrally implemented withthe control functions performed by the knob. A basic force sensation isforce detents that are output at particular rotational positions of theknob to inform the user how much the knob has rotated and/or todesignate a particular position of the knob. The force detents can besimple jolts or bump forces to indicate the detent's position, or thedetents can include forces that attract the knob to the particularrotational detent position and resist movement of the knob away fromthat position. The position can correspond to a particular radio stationfrequency or other station (e.g., television station frequency), thusmaking selection easier for the user. Such detents can be provided foradditional functions, such as volume control for sound speakers, fastforward or rewind of a video cassete recorder or computer-displayedmovie (such as a DVD movie), scrolling a displayed document or web page,etc. Force feedback “snap-to” detents can also be provided, for example,for the favorite station frequencies preprogrammed by the user, where asmall force biases the knob to the detent position when it is justoutside the position.

Also, the magnitude of the force detents can differ based on the valuebeing controlled. For example, a radio frequency having a higher valuemight be associated with a stronger force detent, while a lower radiofrequency might be associated with a weaker force detent when it isdisplayed, thus informing the user generally of the radio station beingdisplayed without requiring the user to look at the display 14 (which isparticularly useful when operating the device 10 while performinganother task, such as driving a vehicle). In some embodiments, the usercan also change the magnitude of detents associated with particularvalues, such as radio stations, to preferred values so as to “mark”favorite settings. Programmability of the location of the detents in therotary degree of freedom is also convenient since preferred radiofrequencies are most likely spaced at irregular intervals in the radiofrequency range, and the ability to program the detents at any locationin the range allows the user to set detents to those preferred stations.In addition, the knob can be moved by the actuator 70 to select thenearest preprogrammed station or preferred setting. Also, different setsof detent force profiles can be stored in a memory device on the device30 and a particular set can be provided on the knob 18 by amicroprocessor or other controller in the device 30.

Another type of force sensation that can be output on knob 18 is aspring force. The spring force can provide resistance to rotationalmovement of the knob ill either direction to simulate a physical springon the knob. This can be used, for example, to “snap back” the knob toits rest or center position after the user lets go of the knob, e.g.once the knob is rotated past a particular position, a function isselected, and the user releases the knob to let the knob move back toits original position. A damping force sensation can also be provided onknob 18 to slow down the rotation of the knob, allowing more accuratecontrol by the user. Furthermore, any of these force sensations can becombined together for a single knob 18 to provide multiple simultaneousForce effects.

The spring return force provided in the rotary degree of freedom of theknob 18 can also be used to implement a rate control paradigm. “Ratecontrol” is the control of a rate of a function, object, or settingbased on the displacement of the knob 18 from a designated originposition. The further the knob is moved away from the origin position,the greater the rate of change of controlled input. For example, if arate control knob 18 with a spring return force is used to control theradio frequency, then the further the knob is moved from the centerorigin position, the faster the radio frequency will change in theappropriate direction. The frequency stops changing when the knob isreturned to the origin position. The spring force is provided so thatthe further the user moves the knob away from the origin position, thegreater the force on the knob in the direction toward the originposition. This feels to the user as if he or she is inputting pressureor force against the spring rather than rotation or displacement, wherethe magnitude of pressure dictates the magnitude of the rate. However,the amount of rotation of the knob is actually measured and correspondsto the pressure the user is applying against the spring force. Thedisplacement is thus used as an indication of input force.

This rate control paradigm differs from the standard knob controlparadigm, which is known as “position control”, i.e. where the input isdirectly correlated to the position of the knob in the rotary degree offreedom. For example, in the radio frequency example, if the user movesthe knob to a particular position, the radio frequency is changed to aparticular value corresponding to the rotary position of the knob. Forcedetents are more appropriate for such a paradigm. In contrast, in therate control example, moving the knob to a particular position causesthe radio frequency to continue changing at a rate designated by theposition of the knob.

Since the spring force and detent forces are programmable and can beoutput as directed by a microprocessor or other controller, a singleknob 18 can provide both rate control and position control overfunctions or graphical objects. For example, a mode selector, such as abutton or the push/pull knob motion, can select whether rate control orposition control is used. One example of a force feedback deviceproviding both rate control (isometric input) and position control(isotonic input) is described in greater detail in co-pending patentapplication Ser. No. 08/756,745, filed Nov. 26, 1996, and incorporatedherein by reference. Such rate control and position control can beprovided in the rotary degree of freedom of the knob 18. Also, if knob18 is provided with force feedback in the transverse degrees of freedomor in the push/pull linear degree of freedom, then the rate control andposition control modes can be provided in those degrees of freedom.

Other force sensations that can be output on knob 18 include forces thatsimulate ends of travel for the knob 18 or inform the user that the endof travel has been reached. For example, as the user rotates the knob inone direction to adjust the radio frequency 22, the end of the radiofrequency range is reached. There is no hard stop on the knob 18 at thisposition, but the actuator 70 can be controlled to output an obstructionforce to prevent or hinder the user from rotating the knob further inthat direction. Alternatively, a jolt force can be output that isstronger in magnitude than normal detents, which informs the user thatthe end of the frequency range has been reached. The user can thencontinue to rotate the knob in that direction, where the displayedfrequency 22 wraps around to the beginning value in the range.

In another alternate embodiment, one or more of the transverse motionsof knob 18 in directions 28 can be actuated. For example, a greaterrange of motion can be provided for each transverse direction of theknob than typically allowed by a hat switch, and a linear or rotaryactuator can be provided to output forces in the transverse degree offreedom, in one or both directions (toward the center position and awayfrom the center position of the knob). For example, one or more magneticactuators or solenoids can be used to provide forces in these transversedirections.

Furthermore, in other embodiments, the pull and/or push motion of knob18 along axis A can be actuated. For example, a jolt force can be outputon the knob in the linear degree of freedom along axis A as the userpushes the knob. Also, the spring return force provided by spring member64 can instead be output using an actuator controlled by amicroprocessor.

It should be noted that the embodiment of FIGS. 3 a and 3 b is not theonly embodiment of the present invention. For example, some embodimentsmay only include the transverse motion of knob 18 and not the pushand/or pull functionality nor the force feedback functionality. Otherembodiments may only include the push and/or pull functions. Yet otherembodiments may only include force feedback with transverse knob motion,or force feedback with push and/or pull functions.

FIG. 4 a is a perspective view of an alternate embodiment 80 of thecontrol knob 18 of the present invention. In embodiment 80, knob 18 iscoupled to shaft 50, which is rigidly coupled to a flex member 82. Flexmember 82 includes a base plate 84 and a plurality of bent portions 86extending from the base plate 84. For example, as shown in FIG. 4 b, theflex member 82 can be formed by cutting out the circular base plate 84and the portions 86 from a unitary piece 85 of material, such as springsteel or stainless steel. The unitary piece is preferably provided as athin sheet. Holes 88 or other apertures can be placed near the ends ofthe portions 86. Referring back to FIG. 4 a, the portions 86 are thenbent such that the holes 88 substantially align with the other holes 88,where the holes 88 are aligned with axis B that extends approximatelyperpendicular to the surface of the base plate 84. The base plate 84 isrigidly coupled to the rotating shaft of the actuator 70.

FIG. 4 c is a side elevational view of the embodiment 80 of FIG. 4 a. Inthe described embodiment, knob 18 is coupled to shaft 50, which extendsthrough a switch 90 and is coupled to the bent portions 86 of the flexmember 82. The switch 90 is preferably similar to the switch 52described above with reference to FIGS. 3 a and 3 b. For example, amicroswitch can be provided on the inside surface of the housing ofswitch 90 for each transverse direction of knob 18 that is to be sensed.The base plate 84 of the flex member 82 is rigidly coupled to shaft 92of actuator 70. The shaft 92 is rigidly coupled to a shaft (not shown)of sensor 76, which has a grounded housing that is coupled to thegrounded housing of actuator 70.

Alternatively, a plurality of sensors can be positioned external to theflex member 82 instead of using switch 90. For example, switches 94 canbe positioned on two or more sides around the flex member 82, dependingon how many directions are to be sensed. Switches 94 can be contactswitches that each detect when the portions 86 move to engage thecontact switch, thus indicating movement of knob 18 in a particulartransverse direction. Alternatively, members can be positioned on shaft50 which extend to the sides of the shaft and which engage electricalcontacts or other sensors. In other embodiments, other switches orsensors can be used, as described above in the embodiment of FIG. 3 a. Aspring (not shown) can also be coupled to the shaft 50, flex member 82,or knob 18 to provide linear motion along the axis B and allow the knob18 to be pushed and/or pulled by the user, as described in theembodiment of FIG. 3 a. Some types of flexible couplings that allowtransverse motion of the knob 18 may also allow linear motion along axisB, such as flexible disc servo couplings, in which case such as springmay not be needed.

In operation, the transverse motion of knob 18 in embodiment 80 operatesas follows. The knob 18 is moved by the user approximately in atransverse direction 28, which causes the shaft 50 to move with the knobby pivoting approximately about the end of the shaft 50 where it iscoupled to the portions 86. Shaft 50 is allowed such movement due to theflexibility in portions 86. In some embodiments, the knob 18 is alsoallowed to translate in a transverse direction 28 as well as or inaddition to pivoting approximately in directions 28. When the knob 18 isrotated about axis B (by the user or the actuator), the shaft 50 rotatesabout its lengthwise axis, causing the flex member 82 to rotate aboutaxis B. Since the portions 86 are stiff in the rotational directionabout axis B, torque output on the shaft 50 and on the flex member 82 istransmitted accurately from actuator 70 to knob 18 and from knob 18 tosensor 76. Thus, the rotation on flex member 92 causes the shaft 92 torotate, which is sensed by sensor 76. The rotational force about axis Boutput by actuator 70 is similarly transmitted from shaft 92, throughflex member 82, to shaft 50 and knob 18.

FIG. 5 is a perspective view of an exemplary embodiment for the slidercontrol 32 as shown in FIG. 1. Slider control 32 includes slider knob 34which may move in a linear degree of freedom as indicated by arrow 36.In the described embodiment, a transmission member 100 is rigidlycoupled to the knob 34 and extends through a slit or opening 102 in thefront panel 12 or other grounded member. Transmission member 100 can becoupled to an actuator, such as linear voice coil actuator 104.

The member 100 can move in and out of a housing 101 of actuator 104 asindicated by arrow 103. The housing 101 preferably includes a centralcore 107 and a number of elongated magnets 109. An armature 105 includesa hollow, cylindrical member having an inner surface which slidinglyengages the core 107. Wrapped around the armature 105 are coils 110 thatare electrically coupled to actuator and/or sensor interfaces. Thearmature 105 is coupled to the transmission member 100 so that thearmature 105 and member 100 can move in a linear fashion as indicated atarrow 103. Other voice coil configurations can also be used, such asdifferently shaped cores, different coil layouts, etc. Voice coilactuator 104 can serve both as a sensor and an actuator. Alternatively,the voice coil can be used only as an actuator, and a separate sensor106 can be used. Separate sensor 106 can be a linear sensor that sensesthe motion or position of an extension 112 that is coupled to thetransmission member 100 and moves linearly when the transmission membermoves. Voice coil actuators such as actuator 104 are described ingreater detail in U.S. Pat. No. 5,805,140, the disclosure of which isincorporated herein by reference. In particular, the operation of thevoice coils as actuators and/or sensors is described therein.

Other types of actuators 104 and transmissions can also be used inslider control 32. For example, a capstan drive and cable transmissioncan provide linear forces on the knob 34. Other types of actuatorssuitable for use with the slider include active actuators, such aslinear current control motors, stepper motors, pneumatic/hydraulicactive actuators, a torquer, etc. Passive actuators may also be used,such as magnetic particle brakes, friction brakes, fluid controlledpassive actuators, or other actuators which generate a dampingresistance or friction in a degree of motion.

Slider knob 34 can also include a button 38 which is used to provideinput to the device 10. In yet other embodiments, the slider knob 34 canbe pushed and/or pulled in a linear degree of freedom approximatelyperpendicularly to the surface of front panel 12. In such an embodiment,a moveable contact switch can be provided between the knob 34 and thetransmission member 100. A spring member can also be provided similarlyto the embodiment of FIGS. 3 a–3 b and 4 a–4 c to bias the knob 34 to aneutral rest position.

The force sensations and modes described above for the rotary knob inFIGS. 3 a–3 b and 4 a–4 c may also be used for the slider control 32 ina linear degree of freedom. For example, force detents can be applied ina position control paradigm as the knob 34 is moved in its linear degreeof freedom. In a rate control paradigm, a spring return force can biasthe knob 34 toward a center origin position, for example the center ofthe range of motion of the knob. The further the user moves the knobfrom the origin position, the greater the spring force opposing thatmotion and the greater the rate of the controlled value changes(increases or decreases). Other force effects include damping forces,texture forces, jolts, obstruction forces, assistive forces, periodicforces such as vibration forces, and end-of-travel forces.

FIGS. 6 a and 6 b are diagrammatic illustrations illustrating detentforce profiles suitable for use with the knobs of device 10. Detentforce profiles can be implemented by a microprocessor or othercontroller based on instructions stored in a computer readable medium,such as a memory circuit, magnetic disk, optical disk, etc. In FIG. 6 a,a detent force profile is shown. The vertical axis F represents themagnitude of force output, where a positive F value indicates force inone direction, and a negative F value indicates force in the oppositedirection. The horizontal axis d represents the distance or position ofthe moved user object (knob) in a degree of freedom, where the originposition O indicates the position of the detent, a positive d is aposition past the origin of the detent in one direction, and a negatived is a position past the origin of the detent in the opposite direction.The curve 124 represents the force output for a single detent over aposition range for the detent. Thus, for example, if the user moves theknob clockwise toward the detent origin O1, the motion may be from theleft toward the origin O1 on the axis d. A force toward the origin isoutput at position P1 at a magnitude −M to assist the user in moving theknob clockwise toward the origin. As the user continues to move the knobclockwise toward the origin O1, the assisting force is decreased inmagnitude until no force is output when the knob is positioned at theorigin position. If the user moves the knob counterclockwise from theorigin position O1 (from right to left), the force will resist suchmotion in an increasing manner until the knob has been moved to positionP1, after which the force magnitude drops to zero. Similarly, on thepositive side of the d axis, if the user rotates the knob clockwise awayfrom the detent origin position O1 (corresponding to movement from leftto right), an increasing magnitude of force is output until the knobreaches the position P2, at which point the force magnitude drops fromits maximum at M to zero. If the user moves the knob counterclockwisefrom position P2 toward the origin O1, the user initially feels a largemagnitude force assisting that movement, after which the assisting forcegradually decreases until it is zero at the origin O1. Preferably, pointP1 is at an equal distance from origin O1 as point P2.

Additional detents may be positioned in the degree of freedom of theknob in successive positions, represented along axis d. For example,curve 126 represents another detent that is encountered shortly afterleaving the previous detent curve 124 when turning the knob in aparticular direction.

A problem occurring with closely spaced detents is that often the usermoves the knob from a first detent to a second detent butunintentionally moves the knob past the second detent due to theassistive detent forces of the second detent. This is because the forcefrom the user required to move the knob past the resistive force of thefirst detent curve is combined with the assistive force of the seconddetent curve, causing the knob to unintentionally move past the secondorigin and past the endpoint of the second detent curve. Furthermore,the same problem occurs when the user moves the knob in the oppositedirection, from the second detent to the first detent. The user mustexert force to overcome the resistance at the last point of the seconddetent curve, which causes the knob to quickly move past the first pointof the first detent curve, where the assistive force is added to themotion to cause the knob to unintentionally move past the lastencountered point of the first detent.

FIG. 6 b shows a detent force profile of the present invention in whichthe detent forces of two successive detents are partially overlapped dueto the detents, and provide a hysteresis-like force effect. The twodetent curves 128 and 130 are identical, thus allowing a single forcecommand to create the multiple detents if desired. Endpoint 131 of curve128 is positioned at position P1 and endpoint 132 of curve 128 ispositioned at position P2, where P2 is about the same distance fromorigin O1 as P1. Similarly, endpoint 134 of curve 130 is positioned atposition P3 and endpoint 133 of curve 130 is positioned at position P4,where P4 is about the same distance from origin O2 as P3. Detent curve128 ends at endpoint 132 on the right side of origin O1 and within therange of forces of detent curve 130. Preferably, the end point 132 ofcurve 128 is positioned well after the endpoint 134 of curve 130, suchthat the point 132 has a position in the middle of the range betweenpoint 134 and the origin O2. The overlapped zone is between positions P3and P2. In addition, the end point 132 of the first detent preferablydoes not extend past the origin O2 of the second detent into thepositive side of the second detent. If another detent is positionedfurther on the d axis after curve 130, the end point 133 of curve 130preferably is positioned well after the starting endpoint of the nextdetent curve and not past the origin of the next detent curve. Similarpositioning can be provided for curves before curve 128 on axis d.

To solve the problem of unintentionally moving past a successive detent,the range of the second or successive detent is adjusted such that alesser magnitude is preferably output at the beginning of the successivedetent than would normally be output if the entire curve of thesuccessive detent were used. Furthermore, the force detent curve used tooutput force is preferably different depending on the direction of theknob, similar to a hysteresis effect. As shown in FIG. 6 c, when movingthe knob so the knob position changes from left to right, the force atthe beginning of the range of detent curve 130 is at point 135 having amagnitude of 0.5 M, which is one-half the magnitude M of the force atthe other endpoint 133 of the range of curve 130 (ignoring the signs ordirection of the forces). Of course, in other embodiments point 135 canhave a magnitude of other fractions of M, such as one-third orthree-fourths of M. Additional curve 127 can be similarly positioned andprovide a similar overlap with curve 130, and additional curves may beadded before curve 128 and/or after curve 127.

As shown in FIG. 6 d, when moving the knob in the other direction so theknob position changes from right to left, the endpoints of the curve 130reverse in magnitude with respect to the endpoints shown in FIG. 6 c. InFIG. 6 d, starting from origin O2, the force at the beginning of therange of detent curve 128 is at point 136 having a magnitude of 0.5 M,which is one-half the magnitude M of the force at the other endpoint 131of curve 128 (other fractions of M can be provided for endpoint 136 inother embodiments). Any additional curves, such as curve 127, can beprovided with a similar overlap. The force output on the knob thuschanges depending on the direction of the knob. In a digital sensingsystem (e.g. using a digital encoder), the direction can be determinedfrom a history of sensed values. For example, one or more sensedposition values can be stored and compared to a current sensed positionto determine the knob direction.

The use of a lesser magnitude at the beginning of the second detentreduces the tendency of the user to unintentionally skip past a seconddetent after moving the knob over a first detent closely spaced to thesecond detent. For example, when moving the knob left to right (e.g.,clockwise) from position P1, a first detent (curve 128) ends at point132 of curve 128, after which the force magnitude of point 135 on curve130 begins assisting the knob's movement. This magnitude is less thanthe magnitude of the “original” beginning point 134, i.e. the beginningpoint of the full curve 130. Thus, less force is assisting the user tomove toward the origin O2 of curve 130 than if the force magnitude forbeginning point 134 of the curve 130 were in effect. With less forceassisting motion toward origin O2, the user has an easier time slowingdown the knob and preventing the knob from unintentionally overshootingthe origin O2. Furthermore, the changing of endpoints of the detentcurve, as dependent on direction, provides a hysteresis-like effect thereduces the unintentional skip in both directions. Thus, when moving theknob from right to left (e.g., counterclockwise) starting at origin O2,a first detent (curve 130) ends at point 134 of curve 130, after which amagnitude of point 136 on curve 128 begins assisting the knob'smovement. This magnitude is less than the magnitude of the “original”beginning point 134. Thus, less force is assisting the user to movetoward the origin O1 of curve 128 than if the force magnitude forbeginning point 132 of the curve 128 were in effect. With less forceassisting motion toward origin O1, the user has an easier time slowingdown the knob and preventing the knob from unintentionally overshootingthe origin O1.

The same overlapping and hysteresis feature can be provided fordifferently-shaped detents as well, such as curved detents of FIGS. 7a–7 e, detents having deadbands around the origin O, and/or other-shapedforce profiles. In embodiments having detent endpoints that are spacedfurther apart, or which have very gradually-sloping curves, the overlapand hysteresis may not be needed since there may be enough space in thedegree of freedom for the user to control the knob from unintentionallymoving past the next detent.

FIG. 7 a is a graph illustration 137 of a periodic wave 139 that can beused to provide a variety of detent force sensations for use with theknob control device of the present invention. The periodic waverepresents force exerted on the knob (axis F) vs. the position ordisplacement (axis d) of the knob, similar to the force detent profileshown in FIGS. 6 a and 6 b. The wave 139 is a periodic function, such asa sine wave, triangle wave, square wave, etc. In FIG. 7 a, a sine waveshape is shown. In the present invention, a portion of the wave may beused to provide detent and other force sensations for the knob 18 or 34.Various parameters of the sine wave are shown in FIG. 7 a, includingperiod and magnitude.

Curve 138 (solid line) represents a detent force effect that has beencreated based on the sine wave 139. Curve 138 has a width, which is theamount of the wave 139 along axis d used for the force detent. Thelocation of the detent is the position in the degree of freedom at whichthe detent force is centered, i.e. the location of the origin position Oof the detent. A deadband can be defined to be a distance from theorigin O to a specified point, a region in which zero forces are outputon the knob. Thus, the curve 138 shown in FIG. 7 a shows a detent forcestarting at a magnitude M1 at location P1 and, when the knob is movedtoward the origin O, the force increases to the maximum point M2 atlocation P2 and then decreases until point P3, where the deadband isreached (zero magnitude). Similarly, at point P14 on the other side ofthe origin O, the force increases from zero to a maximum magnitude M5 atlocation P5, after which the force drops a short distance to magnitudeM6 at location P6. The force then drops to zero for increasing d, untilanother detent effect is encountered. The small decreases in forcemagnitude from the maximum magnitude at the end points of the curve 138are useful in some detent embodiments to provide a less extremeassistive or resistive force to the user when entering or exiting thedetent range, e.g., to gradually lead the user into the detent rangebefore outputting the maximum force. This can provide a smoother-feelingand, in some cases, a more easily-selected detent (i.e., it can beeasier to position the knob at the detent's origin).

The detent curve 138 can thus be defined using the parameters shown inFIG. 7 a. For example, a force command protocol can provide a number ofdifferent commands that can cause the output of different forcesensations to the user. The commands can each include a commandidentifier followed by one or more command parameters that define andcharacterize the desired force sensation. An example of a commanddefining a detent curve 138 is as follows:

DETENT (TYPE, PERIOD, MAGNITUDE, LOCATION, DEADBAND, FLAG, WIDTH, PHASE,OFFSET, LOCATION, INCREMENT, ARRAY POINTER)

The DETENT identifier indicates the type of force sensation. The TYPEparameter indicates a type of periodic wave from which to base the forcedetent curve, such as a sine wave, triangle wave, square wave, ramp,etc. The PERIOD and MAGNITUDE parameters define those characteristics ofthe periodic wave. The LOCATION parameter defines the location of theorigin position for the detent in the degree of freedom of the knob. TheDEADBAND parameter indicates the size of the deadband around the originposition. The FLAG parameter is a flag that indicates whether the detentis provided on the positive side, the negative side, or both sidesaround the location (origin position). The WIDTH parameter defines theamount of the wave 139 used for the detent curve, i.e. the extent of thewave used starting from the PHASE position. The PHASE parameterindicates the starting position of the detent curve 138 on the wave 139(and is described in greater detail below). The OFFSET parameterindicates the amount of magnitude offset that curve 138 includes fromthe d axis, and is described in greater detail below. The INCREMENTparameter indicates the distance in the degree of freedom of the knobbetween successive detent locations. The optional LOCATION ARRAY POINTERparameter indicates a location in a separate array that has beenpreviously programmed with the particular positions in the degree offreedom of the knob at which the detents are located and (optionally)the total number of detents; the array can be provided in memory, suchas RAM, or other writable storage device. For example, the array can bepreprogrammed with three detents, at locations of 45 degrees, 78degrees, and 131 degrees in the rotation of the knob. The array can beaccessed is necessary to retrieve these locations at which detent forcesare to be output. This can be useful when the detent locations are notevenly or regularly spaced in the degree of freedom, and/or when aparticular number of detents is desired to be output.

Furthermore, in other embodiments, a periodic wave can be additionally“shaped” to form a particular detent curve. For example, an “envelope”can be applied to a periodic wave to shape the wave in a particular way.One method of shaping a wave is to define a first magnitude and a settlewidth, which is the distance required for the wave to settle to asecond, lesser magnitude from the first magnitude. This settle widththus provides a ramping shape to the upper and/or lower portions of theperiodic wave about axis d. Although such shaping is performed in aspatial domain, it is similar to the force signal shaping in the timedomain described in co-pending U.S. patent application Ser. No.08/747,841, incorporated herein by reference. Such shaping is alsodescribed in co-pending U.S. patent application Ser. Nos. 08/846,011 and08/877,114, incorporated herein by reference. The shaping can bespecified by parameters in a commands, such as a settled widthparameter, magnitude parameters, etc.

The detent command can be sent by a supervisory microprocessor to alower-level local microprocessor to decode and interpret the commands tocontrol procedures provided in device 10 in firmware or other storagemedium, as described with reference to FIG. 8 below. If a host computerand local microprocessor are used, the host computer can send thecommand to the local microprocessor, which parses/decodes and interpretsthe command and causes appropriate forces to be output. Commands andprotocols for use in force feedback are described in greater detail inU.S. Pat. No. 5,734,373, incorporated by reference herein. Such commandscan also be retrieved from a storage device such as memory and thenparsed and interpreted by a local microprocessor.

The ability to define a force detent (in the spatial domain) in terms ofa periodic waveform can be useful in force feedback implementations inwhich periodic force effects in the time domain are also provided. Forexample, vibration force sensations can be provided by outputting aperiodic sine wave or square wave for the magnitude of the force overtime. If such time-based effects can be output on knob 18 or 34, then itis convenient to use the same periodic wave definitions and data fordefining force vs. position profiles for detents as shown in FIGS. 7 a–7e.

FIG. 7 b is a graph illustration 140 showing particular parameters ofthe detent command described above which are applied to a periodic wave.Sine wave 142 has a magnitude and period as shown. A specified phase ofthe desired detent curve causes the detent curve to start at a positionon wave 142 in accordance with the phase. For example, in FIG. 7 b, aphase of 50 degrees is specified. This will cause the resulting detentcurve to start at point P on the wave 142. A width parameter specificsthe amount of the wave from the phase location to be used as the detentcurve. Furthermore, an offset of −0.8 is indicated. This causes theresulting detent curve to be shifted down by 80% from the wave 142.Furthermore, a deadband is also specified (not shown in FIG. 7 b.).

FIG. 7 c is a graph 144 showing the resulting detent curve 146 obtainedfrom the application of the parameters to the wave 142 described withreference to FIG. 7 b. The portion of the wave 142 starting at the phaseand positioned above the offset line in FIG. 7 b is used in the detentcurve 146. Furthermore, a deadband 148 has been added to the curve. Theflag in the detent command has caused the positive side of the curve 146to be mirrored on the negative side of the origin O. This detent curve146 causes a detent force that is similar to the detent force describedwith reference to FIG. 7 a, only smaller in magnitude and in positionrange over the degree of freedom of the knob.

FIG. 7 d is a graph 160 showing a periodic wave and parameters to beapplied to the wave. Sine wave 162 is provided as described above,having a particular period and magnitude. An offset is specified for theresulting detent curve; in the example of FIG. 7 d, the offset is 1,thus causing the detent curve to be shifted upward by its entiremagnitude. A phase of 270 degrees is also indicated, so that the detentcurve starts at the lowest magnitude of the wave 172 at point P.Furthermore, an increment is also specified as a parameter (not shown).FIG. 7 e is a graph 170 illustrating the detent curves 172 and 174resulting from the wave 162 and parameters described with reference toFIG. 7 d. The portion of the wave 162 past point P and ending at a pointdefined by a width parameter is provided both on the positive side andthe negative side of origin O1 of graph 170 for curve 172 (the positiveand negative sides are designated by the flag parameter). A second curve174 is also shown, where the origin O2 of the second curve is positionedat a distance from the origin O1 as specified by the incrementparameter. Additional curves similar to curves 172 and 174 are providedat further distances at same increment from each other. The detentcurves 172 and 174 provide a much steeper, less gradual detent forceover the detent range than the other detent forces shown in FIGS. 7 aand 7 c. Furthermore, no actual deadband is specified, although theshape or each half of the curve 172 provides a small zone 176 where zeroforce is output, similar to a deadband.

FIG. 8 is a block diagram illustrating an electromechanical system 200for the device 10 of FIG. 1 suitable for use with the present invention.A force feedback system including many of the below components isdescribed in detail in co-pending patent application Ser. No.09/049,155, filed Mar. 26, 1998, and U.S. Pat. No. 5,734,373, which areboth incorporated by reference herein in their entirety.

In one embodiment, device 10 includes an electronic portion having alocal microprocessor 202, local clock 204, local memory 206, sensorinterface 208, and actuator interface 210.

Local microprocessor 202 is considered “local” to device 10, where“local” herein refers to processor 202 being a separate microprocessorfrom any other microprocessors, such as in a controlling host computer(see below), and refers to processor 202 being dedicated to forcefeedback and/or sensor I/O for the knob 18 of the interface device 10.In force feedback embodiments, the microprocessor 202 reads sensorsignals and can calculate appropriate forces from those sensor signals,time signals, and force processes selected in accordance with a hostcommand, and output appropriate control signals to the actuator.Suitable microprocessors for use as local microprocessor 202 include the8X930AX by Intel, the MC68HC711E9 by Motorola and the PIC16C74 byMicrochip, for example. Microprocessor 202 can include onemicroprocessor chip, or multiple processors and/or co-processor chips,and can include digital signal processor (DSP) functionality. Also,“haptic accelerator” chips can be provided which are dedicated tocalculating velocity, acceleration, and/or other force-related data.Alternatively, fixed digital logic and/or state machines can be used toprovide similar functionality.

A local clock 204 can be coupled to the microprocessor 202 to providetilling data, for example, to compute forces to be output by actuator70. In alternate embodiments using the USB communication interface,timing data for microprocessor 202 can be retrieved from the USBinterface. Local memory 206, such as RAM and/or ROM, is preferablycoupled to microprocessor 202 in interface device 10 to storeinstructions for microprocessor 202, temporary and other data,calibration parameters, adjustments to compensate for sensor variationscan be included, and/or the state of the device 10. Display 14 can becoupled to local microprocessor 202 in some embodiments. Alternatively,a different microprocessor or other controller can control output to thedisplay 14.

Sensor interface 208 may optionally be included in device 10 to convertsensors signals to signals that can be interpreted by the microprocessor202. For example, sensor interface 208 can receive signals from adigital sensor such as an encoder and convert the signals into a digitalbinary number. An analog to digital converter (ADC) can also be used.Such circuits, or equivalent circuits, are well known to those skilledin the art. Alternately, microprocessor 202 can perform these interfacefunctions. Actuator interface 210 can be optionally connected betweenthe actuator 70 and microprocessor 202 to convert signals frommicroprocessor 202 into signals appropriate to drive the actuators.Actuator interface 210 can include power amplifiers, switches, digitalto analog controllers (DACs), and other components, as well known tothose skilled in the art. In alternate embodiments, actuator interface210 circuitry can be provided within microprocessor 202 or in theactuator 70.

A power supply 212 can be coupled to actuator 70 and/or actuatorinterface 210 to provide electrical power. In a different embodiment,power can be supplied to the actuator 70 and any other components (asrequired) by an interface bus. Power can also be stored and regulated bydevice 10 and thus used when needed to drive actuator 70.

A mechanical portion is included in device 10, an example of which isshown above in FIGS. 3 a–3 b and 4 a–4 c. The mechanical portion caninclude some or all of the components needed for rotational motion ofknob 18, transverse motion of knob 18, the push and/or pull motion ofknob 18, and force feedback in any or all of these degrees of freedom ofthe knob.

Mechanical portion 200 preferably includes sensors 214, actuator 70, andmechanism 216. Sensors 214 sense the position, motion, and/or othercharacteristics of knob 18 along one or more degrees of freedom andprovide signals to microprocessor 202 including informationrepresentative of those characteristics. Typically, a sensor 214 isprovided for each degree of freedom along which knob 18 can be moved,or, a single compound sensor can be used for multiple degrees offreedom. Sensors 214 can include sensor 76, switch 52, and switch 58 asshown in FIGS. 3 a–3 b. For example, one switch 52 of FIGS. 3 a–3 b orswitch 90 of FIG. 4 c can include a sensor switch for each transversedirection 28 that the knob 18 can be moved. Examples of sensors suitablefor rotary sensor 70 of FIGS. 3 a–3 b and 4 a–4 c include opticalencoders, analog sensors such as potentiometers, Hall effect magneticsensors, optical sensors such as a lateral effect photo diodes,tachometers, and accelerometers. Furthermore, both absolute and relativesensors may be used.

In those embodiments including force feedback, actuator 70 transmitsforces to knob 18 in one or more directions in a rotary degree offreedom in response to signals output by microprocessor 202 or otherelectronic logic or device, i.e., it is “electronically-controlled.” Theactuator 70 produces electronically modulated forces which means thatmicroprocessor 202 or other electronic device controls the applicationof the forces. Typically, an actuator 70 is provided for each knob 18that includes force feedback functionality. In some embodiments,additional actuators can also be provided for the other degrees offreedom of knob 18, such as the transverse motion of the knob 18 and/orthe push or pull motion of the knob. The actuators, such as actuator 70,can include active actuators, such as linear current control motors,stepper motors, pneumatic/hydraulic active actuators, a torquer (motorwith limited angular range), voice coil actuators, etc. Passiveactuators can also be used, including magnetic particle brakes, frictionbrakes, or pneumatic/hydraulic passive actuators, and generate a dampingresistance or friction in a degree of motion. In some embodiments, allor some of sensors 214 and actuator 70 can be included together as asensor/actuator pair transducer, as shown in FIGS. 3 a–3 b for actuator70 and sensor 76.

Mechanism 216 is used to translate motion of knob 18 to a form that canbe read by sensors 214, and, in those embodiments including forcefeedback, to transmit forces from actuator 70 to knob 18. Examples ofmechanism 216 are shown with respect to FIGS. 3 a–3 h and 4 a–4 c. Othertypes of mechanisms can also be used, as disclosed in U.S. Pat. Nos.5,767,839, 5,721,566, 5,805,140, and co-pending patent application Ser.Nos. 08/664,086, 08/709,012, and 08/736,161, all incorporated byreference herein.

Also, a drive mechanism such as a capstan drive mechanism can be used toprovide mechanical advantage to the forces output by actuator 70. Someexamples of capstan drive mechanisms are described in U.S. Pat. No.5,731,804 and co-pending patent application Ser. Nos. 08/961,790,08/736,161, all incorporated by reference herein. Alternatively, a beltdrive system, gear system, or other mechanicalamplification/transmission system can be used.

Other input devices 220 can be included in interface device 10 and sendinput signals to microprocessor 202. Such input devices can includebuttons, such as buttons 16 on front panel 12 as shown in FIG. 1, usedto supplement the input from the knob to the device 10. Also, dials,switches, voice recognition hardware (e.g. a microphone, with softwareimplemented by microprocessor 202), or other input mechanisms can beused, can also be included to send a signal (or cease sending a signal)to microprocessor 202 or to the actuator 70 or actuator interface 210,indicating that the user is not gripping the knob 18, at which point alloutput forces are ceased for safety purposes. Such safety switches aredescribed in U.S. Pat. No. 5,691,898 incorporated by reference herein.

Furthermore, a safety or “deadman” switch 222 can optionally be includedfor the knob 18 in those implementations providing force feedback on theknob. The safety switch prevents forces from being output on the knobwhen the user is not contacting or using it, and to prevent the knobfrom spinning on its own when the user is not touching it. In oneembodiment, the safety switch detects contact of a user's digit (finger,thumb, etc.) with the knob 18. Such a switch can be implemented as acapacitive sensor or resistive sensor, the operation of which is wellknown to those skilled in the art. In a different embodiment, a switchor sensor that detects pressure on the knob 18 from the user can beused. For example, a switch can be sensitive to a predetermined amountof pressure, which will close the switch. Alternatively, a pressuremagnitude sensor can be used as the safety switch, where forces areoutput on the knob only when a pressure magnitude over a minimumthreshold is sensed. A pressure requirement for safety switch 222 hasthe advantage of ensuring good contact between finger and knob beforeforces are Output; output forces are enabled only when the user ismoving or actively using the knob. Thus, if the user simply rests his orher finger lightly on the knob without intending to use it, no forceswill be output to surprise the user.

Other microprocessor 224 can be included in some embodiments tocommunicate with local microprocessor 202. Microprocessors 202 and 224are preferably coupled together by a bi-directional bus 226. Additionalelectronic components may also be included for communicating viastandard protocols on bus 226. These components can be included indevice 10 or another connected device. Bus 226 can be any of a varietyof different communication busses. For example, a bi-directional serialor parallel bus, a wireless link, a network architecture (such asCanbus), or a uni-directional bus can be provided betweenmicroprocessors 224 and 202.

Other microprocessor 224 can be a separate microprocessor in a differentdevice or system that coordinates operations or functions with thedevice 10. For example, other microprocessor 224 can be provided in aseparate control subsystem in a vehicle or house, where the othermicroprocessor controls the temperature system in the car or house, orthe position of mechanical components (car mirrors, seats, garage door,etc.), or a central display device that displays information fromvarious systems. Or, the other microprocessor 224 can be a centralizedcontroller for many systems including device 10. The two microprocessors202 and 224 can exchange information as needed to facilitate control ofvarious systems, output event notifications to the user, etc. Forexample, if other microprocessor 224 has determined that the vehicle isoverheating, the other microprocessor 224 can communicate thisinformation to the local microprocessor 202, which then can output aparticular indicator on display 14 to warn the user. Or, if the knob 18is allowed different modes of control, the other microprocessor 224 cancontrol a different mode. Thus, if the knob 18 is able to control bothaudio stereo output as well as perform temperature control, the localmicroprocessor 202 can handle audio functions but can pass all knobsensor data to other microprocessor 224 to control temperature systemadjustments when the device 10 is in temperature control mode.

In other embodiments, other microprocessor 224 can be a microprocessorin a host computer, for example, that commands the local microprocessor202 to output force sensations by sending host commands to the localmicroprocessor. The host computer can be a personal computer,workstation, video game console, or other computing or display device,set top box, “network-computer”, etc. Besides microprocessor 224, thehost computer preferably includes random access memory (RAM), read onlymemory (ROM), input/output (I/O) circuitry, and other components ofcomputers well-known to those skilled in the art. The host computer canimplement a host application program with which a user interacts usingknob 18 and/or other controls and peripherals. The host applicationprogram can be responsive to signals from knob 18 such as the transversemotion of the knob, the push or pull motion, and the rotation of theknob (e.g., the knob 18 can be provided on a game controller orinterface device such as a game pad, joystick, steering wheel, or mousethat is connected to the host computer). In force feedback embodiments,the host application program can output force feedback commands to thelocal microprocessor 202 and to the knob 18. In a host computerembodiment or other similar embodiment, microprocessor 202 can beprovided with software instructions to wait for commands or requestsfrom the host computer, parse/decode the command or request, andhandle/control input and output signals according to the command orrequest.

For example, in one force feedback embodiment, host microprocessor 224can provide low-level force commands over bus 226, which microprocessor202 directly transmits to the actuators. In a different force feedbacklocal control embodiment, host microprocessor 224 provides high levelsupervisory commands to microprocessor 202 over bus 226, andmicroprocessor 202 manages low level force control loops to sensors andactuators in accordance with the high level commands and independentlyof the host computer. In the local control embodiment, themicroprocessor 202 can independently process sensor signals to determineappropriate output actuator signals by following the instructions of a“force process” that may be stored in local memory 206 and independentlycalculation instructions, formulas, force magnitudes (force profiles),and/or other data. The force process can command distinct forcesensations, such as vibrations, textures, jolts, or even simulatedinteractions between displayed objects. Such operation of localmicroprocessor in force feedback applications is described in greaterdetail in U.S. Pat. No. 5,734,373, previously incorporated herein byreference.

In an alternate embodiment, no local microprocessor 202 is included ininterface device 10, and a remote microprocessor, such as microprocessor224, controls and processes all signals to and from the components ofinterface device 10. Or, hardwired digital logic can perform anyinput/output functions to the knob 18.

While this invention has been described in terms of several preferredembodiments, there are alterations, modifications, and permutationsthereof which fall within the scope of this invention. It should also benoted that the embodiments described above can be combined in variousways in a particular implementation. Furthermore, certain terminologyhas been used for the purposes of descriptive clarity, and not to limitthe present invention. It is therefore intended that the followingappended claims include such alterations, modifications, andpermutations as fall within the true spirit and scope of the presentinvention.

1. A device comprising: a manipulandum operable to be displaced in adegree of freedom; a means for sensing a displacement of saidmanipulandum in said degree of freedom; a means for selecting a modeassociated with said displacement of said manipulandum in said degree offreedom, said mode comprising at least one of a position control modeand a rate control mode; an actuator operable to output aprocessor-controlled force sensation to said manipulandum, said forcesensation associated with said mode; and a processor operable to receivea sensing signal from said sensing means and to output to the actuator acontrol signal associated with the sensing signal, the control signaloperable to cause said actuator to output the processor-controlled forcesensation, said processor further operable to associate a value with aposition of said manipulandum in said position control mode and tocontrol a rate of change of said value in said rate control mode.
 2. Thedevice as recited in claim 1, wherein said degree of freedom comprises alinear degree of freedom.
 3. The device as recited in claim 1, whereinsaid degree of freedom comprises a rotary degree of freedom.
 4. Thedevice as recited in claim 3, wherein said manipulandum is operable tobe displaced in a plurality of transverse directions with respect to anaxis of said rotary degree of freedom.
 5. The device as recited in claim4, wherein said sensing means comprises a hat switch comprising aplurality of individual switches, each of said individual switchesoperable to detect a transverse position of said manipulandum in one ofthe plurality of said transverse directions.
 6. The device as recited inclaim 1, wherein the processor is operable to control said forcesensation in said rate control mode.
 7. The device as recited in claim1, wherein said force sensation comprises at least one of a biasingforce, a damping force, a texture force, a jolt, an obstruction force,an assistive force, a periodic force, and an end-of-travel force.
 8. Thedevice as recited in claim 1, wherein said actuator is operable tooutput a force detent during said displacement of said manipulandum insaid position control mode.
 9. The device as recited in claim 1, whereinsaid rate of change is associated with said displacement of saidmanipulandum with respect to a designated position of said manipulandum.10. The device as recited in claim 9, wherein said processor is operableto control a biasing force applied to said manipulandum in a directiontoward said designated position in said rate control mode, and wherein avalue of said rate of change comprises zero at said designated position.11. The device as recited in claim 1, wherein said processor is operableto control said position of said manipulandum in said rate control mode.12. The device as recited in claim 1, wherein the processor comprises afirst processor and a second processor, the first processor operable tocontrol the second processor.
 13. The device as recited in claim 1,wherein the degree of freedom comprises a first degree of freedom and asecond degree of freedom.
 14. A method comprising: providing amanipulandum; providing an actuator operable to output a force to saidmanipulandum; providing a sensor operable to detect a position of saidmanipulandum and to output a sensor signal, said sensor signalcomprising information associated with said position; and providing aprocessor operable to control said actuator and to receive said sensorsignal from said sensor, said processor operable to associate a valuewith said position of said manipulandum in a position control mode andto control a rate of change of said value in a rate control mode.
 15. Amethod comprising: providing a manipulandum operable to be displaced ina first degree of freedom and a second degree of freedom; providing ameans for selecting a mode associated with a position of saidmanipulandum, said mode comprising at least one of a position controlmode and a rate control mode; providing an actuator operable to output aprocessor-controlled force sensation to said manipulandum, said forcesensation associated with said mode; and providing a processor operableto control said force sensation output from said actuator and to receivea signal from a sensing means, said processor operable to associate avalue with a position of said manipulandum in said position control modeand to control a rate of change of said value in said rate control mode.16. A method comprising: providing a manipulandum operable to bedisplaced in a degree of freedom; providing a means for sensing adisplacement of said manipulandum in said degree of freedom; providing ameans for selecting a mode associated with said displacement of saidmanipulandum in said degree of freedom, said mode comprising at leastone of a position control mode and a rate control mode; providing anactuator operable to output a processor-controlled force sensation tosaid manipulandum, said force sensation associated with said mode; andproviding a processor operable to receive a sensing signal from saidsensing means and to output to the actuator a control signal associatedwith the sensing signal, the control signal operable to cause saidactuator to output the processor-controlled force sensation, saidprocessor further operable to associate a value with a position of saidmanipulandum in said position control mode and to control a rate ofchange of said value in said rate control mode.